1. Field of the Invention
The present invention relates to a display device which performs a display control of pixels using thin film transistors (TFT), and a manufacturing method of the display device.
2. Description of the Related Art
Conventionally, various studies have been made to enhance the performance such as electric characteristics of a thin film transistor made of amorphous silicon (a-Si). Here, to impart desired electric characteristics to a thin film transistor, for example, the studies have been also made toward the improvement of electron mobility or the like by increasing a crystal grain size of silicon while making use of a manufacturing process which is designed so as to maintain the structure of a thin film transistor to be made of amorphous silicon.
JP-A-5-55570 (patent document 1) discloses one example of such a related part, and FIG. 6 shows a thin film transistor having the bottom gate structure in the same manner as a thin film transistor described in patent document 1. In patent document 1, as shown in FIG. 6, a polycrystalline silicon (p-Si) layer is stacked below an amorphous silicon layer due to reasons attributed to the manufacture of the display device.